When a client has a need or idea that other people might benefit from, it's a great opportunity to contribute a module back to the community. I recently created the new Autocreate Access module to solve a problem on a project where Drupal's autocomplete tagging widget for taxonomy terms didn't work as our client expected. Typically, Drupal sites utilise this field widget to allow users to create new categories for their content on the fly...
In Drupal 7, we had menu_get_object() to get the object in code for whichever node, term, or whatever entity makes up the current page. But in Drupal 8, that has been replaced, and entities can usually be operated on in a generic way. If you know the type of entity you want, it's pretty simple. But I keep running into different suggestions of how to get the entity object when you don't know its type. Given that D8 allows us to deal with entities in a unified way, I thought there must be a good way! The code of core itself is usually the best place to look for examples of how to do common things.
In a recent Drupal 8 project, one of the site's vocabularies had several thousand terms in it (representing airports), which caused its admin listing page to run out of memory before it could render. I wanted to solve this without affecting any other vocabularies on the site, and improve the listing itself along the way to be more useful, with filters to make searching it much easier. The original listing is not a view, and loads much more than it needs to. Here's the customised page for airports that I wanted to head towards: